/*
* This program is free software; you can redistribute it and/or modify it under the terms of
* the GNU AFFERO GENERAL PUBLIC LICENSE as published by the Free Software Foundation; either version 3 of the License,
* or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU AFFERO GENERAL PUBLIC LICENSE for more details.
* You should have received a copy of the GNU AFFERO GENERAL PUBLIC LICENSE along with this program;
* if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
package com.meidusa.amoeba.parser.expression;
/**
* �������ʽ
*
* @author <a href=mailto:piratebase@sina.com>Struct chen</a>
*
*/
@SuppressWarnings("unchecked")
public class ConstantExpression extends Expression {
private Comparable value;
public ConstantExpression(Comparable value) {
this.value =value;
}
@Override
public Comparable evaluate(Object[] parameters) {
return value;
}
public boolean canEvaluate(){
return true;
}
@Override
public Expression reverse() {
return this;
}
@Override
protected void toString(StringBuilder builder) {
Comparable temp = value;
if(value instanceof String){
temp = "'"+temp+"'";
builder.append("'");
builder.append(value);
builder.append("'");
}else{
builder.append(temp != null?temp.toString():"null");
}
}
public boolean isRealtime(){
return false;
}
}